71/72 b body rear in an abody?

I just realized you're talking about a '70 Dart. That wide of a rear end is going to wreak havoc with fitting rims on a Dart. The backspacing you'd need is still in the 7" range. The best you can do on a Torque Thrust M is 6.77" of backspace on a 17x9", which is going to put it closer to the quarters than you want. I'm not sure that you could get a tire to fit that without rubbing. A 245/45/17 might work, but that's a pretty narrow tire for a 17x9. The best you can do with a TTM in 17x8 is 5.68, which isn't even close to enough backspacing.

You might be able to make a 61.75" wide rear work in a Duster or Barracuda, but on a Dart it's just going to be a headache. I'd pass on this one.